This research proposal is aimed at obtaining new insights into interactions between the cytoskeletal system and the cell surface. Emphasis will be placed upon the association of intermediate filaments (IF) with cell surface components of cultured animal cells and tissues. In epithelial cells such as keratinocytes, IF-desmosome interactions, as well as IF-submembranous microfilament interactions, will be stressed. In cultured fibroblasts IF-microfilament interactions will be emphasized. These studies will employ a variety of methodologies including cell culture (primary mouse keratinocytes, chicken embryo fibroblasts etc.); the isolation and biochemical characterization of IF and desmosomes from cultured cells and tissues; the production and use of monoclonal and polyclonal antibodies; the use of human autoantibodies; immunofluorescence microscopy of cultured cells and frozen tissue sections; immunogold labeling for electron microscopy; and video tape analyses of light microscopic observations of living cells. The overall goals of these investigations are to study the assembly and disassembly of IF-desmosome complexes in vivo using the primary mouse epidermal cell culture system; to attempt to isolate and biochemically characterize complexes of IF and associated desmosomal proteins utilizing both cultured keratinocytes and bovine tissues; and to study the association between IF and submembranous microfilaments in fibroblasts and skin cells using morphological, biochemical and immunological techniques. The results of these studies should shed new light on the mechanisms underlying cytoskeletal-cell surface interactions which are most likely involved in various physiological activities including cell adhesion, the transfer of information from the cell surface to the cytoplasm, cell-cell communication, and the continuity of cytoskeletal systems from cell to cell.